Microwave is a sort of electromagnetic wave which frequency is 300MHz to 300GHz .The water molecule in medium materials is polar molecule,under the effect of the rapid change of electromagnetic field,its polarity orientation will alter with the changes of the external electric field with the high-speed,causing the movement and friction of molecule.so that the microwave field energy can be converted to heat energy in medium to rise the temperature of materials.accomplishing heating ,puffing and a series of physical and chemical processes ,and so ,microwave heating is achieved.

2,The advantage of the microwave dryer for the chemical

1, Fast heating. Microwave heating is completely different with traditional heating mode. It makes heating medium become heater, do not need heat transfer process. Although thermal conductivity is poor materials, also can achieve heating temperature in a very short time.

2,Save energy and efficiency. Because materials contain water absorb microwave easily and fever, so in addition to a small amount of transmission loss outside, almost no other loss, so high thermal efficiency, save energy.

3, Heating evenly. No matter how shape of each part of the body, microwave heating all can make the object and evenly infiltration and electromagnetic wave list to produce the heat. So heating good uniformity, won't appear the endogenous phenomenon focal.

4, Mouldproof, sterilization, fresh. Microwave heating has thermal and biological effect, can sterilize and mould proof in low temperature. Due to heating rapidly, the time is short, can maximum limit save material activity and the vitamin original colour and lustre and nutrition of food.